I don't usually do jokes, but I hadn't heard this one.
"Where am I?" asks the atheist.
"Beg your pardon?" the other guy asks. "You're in Heaven, of course."
"B-but I don't believe..."
"Hmmm" (squinting his eyes) "are you one of them atheist folk?" the gatekeeper asks, his mouth curling in mild distaste.
"Yes, I am... I believe I'm in the wrong place, which way is the Summerland?" our atheist friend asks.
"It's been 'temporarily' shut down for repairs," the gatekeeper said with an ironic chuckle, "ever since we took over...err...I mean... since the people found their way to the true path."
"Well, that's nice," says the atheist "But what do I do now?"
"I'm sorry sir, but you must go to Hell. No Pagans allowed here."
"WHAT? Hell? But I don't believe in Hell!"
"Sorry, those are the rules, just follow the downward path to the left." So our Pagan friend walks down to Hell, only to find the doors open. He warily goes in and looks around to see beautiful meadows, and animals happily roaming the surrounding woods.
"Hmm, so far so good."
A voice behind him made him all but jump out of his skin. "Can I help you?"
"SHEESH! Give a guy a heart attack, why don't you?"
"Ahem... a little too late for that, isn't it?" the guy said with a smile.
"Who are you, anyway?" our friend asks.
"Why, I'm Satan," the other one said with a slight bow.
"Satan?!" said our friend as he started looking around nervously.
"At your service... you're the atheist guy Pete called us about, right?"
"Pete... oh the guy in Heaven, yes..." he said, eyeing Satan carefully. "What's gonna happen to me now?"
"Well, you can hang out, there's some great fishing going on in the lake beyond these woods and, if you follow the road down this way, there's refreshments and a little market not too far and to your right. There's a massive library with every book ever written, and I believe the atheist meeting grounds are just behind that hill..." Satan went on.
"Are you serious...?" the Pagan finally asked.
Satan grinned at him innocently. "Why shouldn't I be?" Sudden understanding filled Satan's eyes. "You don't believe the rumors, do you?" Suddenly, in answer to our friend's growing fear, the vault of the skies opened with a thunderous groan. A soul, plummeting through the sky, screamed in terror, his screams drowned by the opening of a yawning chasm full of fire and brimstone. The stench of sulfur thickened the air. Thousands of howling, suffering, tortured voices echoed through Hell. When the screaming soul finally fell into the pit, the ground shut closed with a sickening thud that rattled the earth.
Our Pagan friend all but soiled his undies as he yelped in terror. "And what was THAT all about?"
Satan rolled his eyes, and made a dismissive gesture with his hand as he said with a distasteful grimace. "Oh, just ignore that...it was a Christian. They refuse to have it any other way!"